Received slow scan TV images from ISS while I was sleeping / 2017-07-21

I read about the current
ARISS Celebrates it’s 20th Anniversary through SSTV Event
and noticed the planned times weren't really compatible with my day/night
cyclus. I know, as a hardcore radio amateur I should be up at the weirdest
hours for rare events but I also like my sleep a lot and my wife really
dislikes alarms at weird hours.

Automation to the rescue: I decided to record all of a night of ISS signals
on the computer with audacity and decode images from it later.
The computer adjusted the radio for doppler using gpredict. Since
I don't have an automatic rotor for satellite antennas I used the VHF/UHF
vertical. This may seem strange but the weakest signals from ISS are when
it is right above the horizon (which is when the vertical has the best
reception). And as noticed on earlier SSTV events that compared
to other amateur satellites the ISS has a strong signal.

So I left it running for a night and checked the results afterwards. The result
was a 9 hour recording and audacity decided to hang after stopping the
recording. I made a backup copy of the audio data just to be safe and restarted
audacity. Luckily it recovered the project fine after restarting.

With a recent version of qsstv
I decoded the recorded audio and searched for ISS passes in the recording.

The result is 13 decodes in one night. It turns out it received audio from a
number of low passes that I did not see in gpredict because I have gpredict set
up to skip low passes (those that don't come above a 20 degree angle above the
horizon). But the strong signals from ISS make those show up in my radio
anyway.